This research would investigate the development in infancy of the ability to perceive visible objects as unitary, bounded, and persisting through time. The first series of experiments focuses on 4-month-old infants' perception of an object that moves fully out of view behind a screen and then returns to sight. Using a habituation of looking time method, the experiments would probe the conditions under which infants perceive such an object to persist in a definite location while it is hidden and to retain its identity when it is revealed. Specifically, the proposed experiments would test whether infants, like adults, perceive the persistence and identity of an object over occlusion by detecting information for the continuity in space and time of the object's path of displacement, the uniqueness of its spatial position, the regularity of its motion, and the constancy of its color, texture, and form. The remaining experiments focus on the origins and the development of object perception. Experiments with newborn infants would investigate whether neonates, like 3-6 month olds, perceive object unity and identity detecting the spatial and kinetic relationships among surfaces in a visual scene. Experiments with infants beyond 6 months would investigate the emergence of abilities to perceive object unity and identity by detecting the static configural properties of surfaces: abilities possessed by adults and preschoolers but not younger infants. Specifically, these experiments would probe whether these abilities develop in a unitary or piecemeal fashion. These experiments are proposed in order to shed light on the development of visual perception and on the origins and early development of an important cognitive capacity: the capacity to conceive the world in terms of objects. The experiments should help to reveal when and how infants first appreciate that the world is composed of entities that are unitary, bounded, persisting, and continuously moveable, entities that exist even at places and times where they cannot be seen.